Extreme paths in oriented 2D Percolation

A useful result about leftmost and rightmost paths in two dimensional bond percolation is proved. This result was introduced without proof in \cite{G} in the context of the contact process in continuous time. As discussed here, it also holds for several related models, including the discrete time contact process and two dimensional site percolation. Among the consequences are a natural monotonicity in the probability of percolation between different sites and a somewhat counter-intuitive correlation inequality

Broadening the Mission: Research Activity among University Labor Education/Labor Studies Professionals

[Excerpt] This study examines research activity among university and college labor education/labor studies professionals. Using data gathered in a survey of faculty employed in the field, the paper presents information concerning the extent and focus of these research activities, the methodologies employed, the outlets for the research products that result, and the factors limiting such work. The findings of this study indicate that research, of both an applied and scholarly nature, is an increasingly significant part of the work of labor education/labor studies professionals. The study concludes with a discussion of the implications this trend has for the labor education/labor studies field, with special attention being given to the role research activity can play in meeting the needs of unions, union members, and union leaders

van der Waals dispersion power laws for cleavage, exfoliation and stretching in multi-scale, layered systems

Layered and nanotubular systems that are metallic or graphitic are known to exhibit unusual dispersive van der Waals (vdW) power laws under some circumstances. In this letter we investigate the vdW power laws of bulk and finite layered systems and their interactions with other layered systems and atoms in the electromagnetically non-retarded case. The investigation reveals substantial difference between `cleavage' and `exfoliation' of graphite and metals where cleavage obeys a $C_2 D^{-2}$ vdW power law while exfoliation obeys a $C_3 \log(D/D_0) D^{-3}$ law for graphitics and a $C_{5/2} D^{-5/2}$ law for layered metals. This leads to questions of relevance in the interpretation of experimental results for these systems which have previously assumed more trival differences. Furthermore we gather further insight into the effect of scale on the vdW power laws of systems that simultaneously exhibit macroscopic and nanoscopic dimensions. We show that, for metallic and graphitic layered systems, the known "unusual" power laws can be reduced to standard or near standard power laws when the effective scale of one or more dimension is changed. This allows better identification of the systems for which the commonly employed `sum of $C_6 D^{-6}$' type vdW methods might be valid such as layered bulk to layered bulk and layered bulk to atom

Effect of weightlessness and radiation on the growth of the wheat coleoptile for the purpose of defining and verifying an experiment suitable for use in a biosatellite

Effects of temperature, X-ray irradiation, and elevated gravity on wheat seedling growt

Target Zones and Exchange Rates: An Empirical Investigation

In this paper we develop an empirical model of exchange rates in a target zone. The model is general enough to nest most theoretical and empirical models in the existing literature. We find evidence of two types of jumps in exchange rates. Realignment jumps are those that are associated with the periodic realignments of the target zone and within-the-band jumps are those that can be accommodated within the current target zone. The exchange rate may jump outside the current target zone band, in the case of a realignment, but when no jump occurs the target zone is credible (there is zero probability of a realignment) and the exchange rate must stay within the band. We incorporate jumps, in general, by conditioning the distribution of exchange rate changes on a jump variable where the probability and size of a jump vary over time as a function of financial and macroeconomic variables. With this more general model, we revisit the empirical evidence from the European Monetary System regarding the conditional distribution of exchange rate changes, the credibility of the system, and the size of the foreign exchange risk premia. In contrast to some previous findings, we conclude that the FF/DM rate exhibits considerable non-linearities, realignments are predictable and the credibility of the system did not increase after 1987. Moreover, our model implies that the foreign exchange risk premium becomes large during speculative crises. A comparison with the Deutschemark/Dollar rate suggests that an explicit target zone does have a noticeable effect on the time-series behavior of exchange rates.

Micro-computed tomography pore-scale study of flow in porous media: Effect of voxel resolution

A fundamental understanding of flow in porous media at the pore-scale is necessary to be able to upscale average displacement processes from core to reservoir scale. The study of fluid flow in porous media at the pore-scale consists of two key procedures: Imaging - reconstruction of three-dimensional (3D) pore space images; and modelling such as with single and two-phase flow simulations with Lattice-Boltzmann (LB) or Pore-Network (PN) Modelling. Here we analyse pore-scale results to predict petrophysical properties such as porosity, single-phase permeability and multi-phase properties at different length scales. The fundamental issue is to understand the image resolution dependency of transport properties, in order to up-scale the flow physics from pore to core scale. In this work, we use a high resolution micro-computed tomography (micro-CT) scanner to image and reconstruct three dimensional pore-scale images of five sandstones (Bentheimer, Berea, Clashach, Doddington and Stainton) and five complex carbonates (Ketton, Estaillades, Middle Eastern sample 3, Middle Eastern sample 5 and Indiana Limestone 1) at four different voxel resolutions (4.4 µm, 6.2 µm, 8.3 µm and 10.2 µm), scanning the same physical field of view. Implementing three phase segmentation (macro-pore phase, intermediate phase and grain phase) on pore-scale images helps to understand the importance of connected macro-porosity in the fluid flow for the samples studied. We then compute the petrophysical properties for all the samples using PN and LB simulations in order to study the influence of voxel resolution on petrophysical properties. We then introduce a numerical coarsening scheme which is used to coarsen a high voxel resolution image (4.4 µm) to lower resolutions (6.2 µm, 8.3 µm and 10.2 µm) and study the impact of coarsening data on macroscopic and multi-phase properties. Numerical coarsening of high resolution data is found to be superior to using a lower resolution scan because it avoids the problem of partial volume effects and reduces the scaling effect by preserving the pore-space properties influencing the transport properties. This is evidently compared in this study by predicting several pore network properties such as number of pores and throats, average pore and throat radius and coordination number for both scan based analysis and numerical coarsened data

Bus Rapid Transit: A Handbook for Partners, MTI Report 06-02

In April 2005, the Caltrans Division of Research and Innovation (DRI) asked MTI to assist with the research for and publication of a guidebook for use by Caltrans employees who work with local transit agencies and jurisdictions in planning, designing, and operating Bus Rapid Transit (BRT) systems that involve state facilities. The guidebook was also to assist to transit operators, local governments, community residents, and other stakeholders dealing with the development of BRT systems. Several areas in the state have experienced such projects ( San Diego , Los Angeles , San Francisco , and Alameda County ) and DRI wished to use that experience to guide future efforts and identify needed changes in statutes, policies, and other state concerns. Caltrans convened a Task Team from the Divisions of Research and Innovation, Mass Transportation, and Operations, together with stakeholders representing many of those involved with the BRT activities around the state. Prior to MTI’s involvement, this group produced a white paper on the topic, a series of questions, and an outline of the guidebook that MTI was to write. The MTI team conducted case studies of the major efforts in California, along with less developed studies of some of the other BRT programs under development or in early implementation phases around the state. The purpose was to clarify those issues that need to be addressed in the guidebook, as well as to compile information that would identify items needing legislative or regulatory action and items that Caltrans will need to address through district directives or other internal measures. A literature scan was used to develop a bibliography for future reference. The MTI team also developed a draft Caltrans director’s policy document, which provides the basis for Caltrans’ actions. This ultimately developed to be a project within a project. MTI submitted a draft document to Caltrans as a final product from the Institute. Task team members and Caltrans staff and leadership provided extensive review of the draft Bus Rapid Transit: A Handbook for Partners. Caltrans adopted a new Director’s Policy and published the document, BRT Caltrans. The MTI “wraparound” report presented below discusses in more detail the process that was followed to produce the draft report. The process was in many ways as much a project as the report itself

Subroutines GEORGE and DRASTC simplify operation of automatic digital plotter

FORTRAN language subroutines enable the production of a tape for a 360-30 tape unit that controls the CALCOMP 566 Digital Incremental Plotter. This provides the plotter with instructions for graphically displaying data points with the proper scaling of axes, numbering, lettering, and tic marking